Influence of lower sheet material strength on joint quality in self-piercing riveting

Self-piercing riveting (SPR) has become a key joining technique for lightweight and high-strength joints, especially in the automotive and aerospace industries. This study investigates how the strength of the lower sheet affects the performance of SPR joints. While the upper sheet remains unchanged, the lower sheet varies using various alloys (AA7075-F, AA2019, BA0270, Mat A, and Mat B). A finite element model developed in Abaqus/Explicit was employed to simulate the SPR process and assess joint performance. Key joint evaluation criteria, such as interlock and remaining thickness, are also discussed. The results indicate that the strength of the lower sheet must reach a certain threshold to ensure proper joint formation. While increasing the lower sheet’s strength can enhance joint quality, excessive material strength may yield an insufficient interlock within the material or even generate a failure of the lower sheet.